The GELLAB-II software system is an exploratory data analysis system for the analysis of sets of 2D electrophoretic protein gel images. It incorporates sophisticated subsystems for image acquisition, processing, database manipulation, graphics and statistical analysis. It has been applied to a variety of experimental systems in which quantitative and qualitative changes, in one or more proteins among hundreds or thousands of unaltered proteins are the basic analytic problem. Keeping track of changes detected using these methods are also a major attribute of the system. A composite gel database may be "viewed" under different exploratory data analysis conditions and statistical differences and subtle patterns elucidated from "slices" of an effectively 3D database. Results can be presented in a variety of tables, plots or derived images and on workstations over wide area networks. Collaboration is continuing on the GELLAB-II technology transfer CRADA with CSPI Inc., for a commercially available system GELLAB-II+ making this technology easily available to cancer researchers on inexpensive PCs. GELLAB-II applications this period include: Ongoing studies of Rett syndrome, serum dioxin study, and fetal alcohol syndrome; Nuclear matrix protein changes in prostate cancer to aid screening and staging of men with prostate cancer; differences between tumorigenic and non- tumorigenic cell lines derived from transgenic animals or human tumors.